DartFigure-Accuracy-Precision

import random
import turtle
wn = turtle.Screen()
 
alex = turtle.Turtle()
alex.speed(0)
interval = 30 # the interval between neighboring rings in pixels
ringNum = 10
alex.hideturtle()
for i in range(ringNum,0,-1):
    alex.penup()
    alex.goto(0,-1*interval*i)
    alex.pendown()
    if i % 2 == 1:
        alex.fillcolor('red')
    else:
        alex.fillcolor('white')
 
    alex.begin_fill()
    alex.circle(interval*i)
    alex.write(i)
    alex.end_fill()
 
 
 
 
#### throw darts
xlist = []
ylist = []
wn = turtle.Screen()
wd = turtle.Turtle()
wd.shape("classic")
wd.color("green")
wd.penup()
 
# mux and muy are the mean value of 2D darts --- accuracy
# sigmax and sigmay are the deviation of the darts -- precision
mux = 100
sigmax = 50
muy = 0
sigmay = 50
 
dartsNum = 10  # the number of darts on the figure
for i in range(dartsNum):
    xlist.append(random.normalvariate(mux, sigmax))
    ylist.append(random.normalvariate(muy, sigmay))
    wd.goto(xlist[i], ylist[i])
    wd.stamp()
 
wn.mainloop()